Have you double checked to be sure you don't have any leaks anywhere? Double the bill seems kinda high for additional diaper washing. If you haven't already, go check all your toilets...put some food coloring in the tank then let it sit, if you have food coloring in the bowl, you have a leaking toilet. Double check the faucets too, be sure there are no leaks in the plumbing or under the sinks or anything.

I agree. Double is really high. When we garden in the summertime, our water bill goes up by $30 at the most, and that's with us watering it 2-3 times a day.